CVE-2025-38733 (GCVE-0-2025-38733)
Vulnerability from cvelistv5
Published
2025-09-05 17:20
Modified
2025-09-29 05:57
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: s390/mm: Do not map lowcore with identity mapping Since the identity mapping is pinned to address zero the lowcore is always also mapped to address zero, this happens regardless of the relocate_lowcore command line option. If the option is specified the lowcore is mapped twice, instead of only once. This means that NULL pointer accesses will succeed instead of causing an exception (low address protection still applies, but covers only parts). To fix this never map the first two pages of physical memory with the identity mapping.
References
Impacted products
Vendor Product Version
Linux Linux Version: 32db401965f165f7c44447d0508097f070c8f576
Version: 32db401965f165f7c44447d0508097f070c8f576
Version: 32db401965f165f7c44447d0508097f070c8f576
Version: 0b99d0e17d6a73a0526f92bc6b54b2b95e67a31d
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{
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          "programFiles": [
            "arch/s390/boot/vmem.c"
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      "descriptions": [
        {
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/mm: Do not map lowcore with identity mapping\n\nSince the identity mapping is pinned to address zero the lowcore is always\nalso mapped to address zero, this happens regardless of the relocate_lowcore\ncommand line option. If the option is specified the lowcore is mapped\ntwice, instead of only once.\n\nThis means that NULL pointer accesses will succeed instead of causing an\nexception (low address protection still applies, but covers only parts).\nTo fix this never map the first two pages of physical memory with the\nidentity mapping."
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        "dateUpdated": "2025-09-29T05:57:01.534Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/93f616ff870a1fb7e84d472cad0af651b18f9f87"
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      ],
      "title": "s390/mm: Do not map lowcore with identity mapping",
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    "cveId": "CVE-2025-38733",
    "datePublished": "2025-09-05T17:20:33.075Z",
    "dateReserved": "2025-04-16T04:51:24.033Z",
    "dateUpdated": "2025-09-29T05:57:01.534Z",
    "state": "PUBLISHED"
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  }
}


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